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  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. #include <time.h>
  30. #include <unistd.h>
  31. #include <ipc/ipc.h>
  32. #include <stdio.h>
  33. #include <arch/barrier.h>
  34.  
  35. #include <sysinfo.h>
  36. #include <as.h>
  37. #include <ddi.h>
  38.  
  39. /* Pointers to public variables with time */
  40. struct {
  41.     volatile sysarg_t seconds;
  42.     volatile sysarg_t useconds;
  43.     volatile sysarg_t useconds2;
  44. } *ktime = NULL;
  45.  
  46.  
  47. /** POSIX gettimeofday
  48.  *
  49.  * The time variables are memory mapped(RO) from kernel, which updates
  50.  * them periodically. As it is impossible to read 2 values atomically, we
  51.  * use a trick: First read a seconds, then read microseconds, then
  52.  * read seconds again. If a second elapsed in the meantime, read
  53.  * useconds again. This provides assurance, that at least the
  54.  * sequence of subsequent gettimeofday calls is ordered.
  55.  */
  56. #define TMAREA (100*1024*1024)
  57. int gettimeofday(struct timeval *tv, struct timezone *tz)
  58. {
  59.     void *mapping;
  60.     sysarg_t seconds,useconds;
  61.     sysarg_t t1;
  62.     int res;
  63.  
  64.     if (!ktime) {
  65.         /* TODO: specify better, where to map the area */
  66.         /* Get the mapping of kernel clock */
  67.         res = ipc_call_sync_3(PHONE_NS, IPC_M_AS_AREA_RECV,
  68.                       TMAREA,
  69.                       PAGE_SIZE,
  70.                       AS_AREA_READ | AS_AREA_CACHEABLE,
  71.                       &t1,&t1,&t1);
  72.         if (res) {
  73.             printf("Failed to initialize timeofday memarea\n");
  74.             _exit(1);
  75.         }
  76.         ktime = (void *) (TMAREA);
  77.     }
  78.     tz->tz_minuteswest = 0;
  79.     tz->tz_dsttime = DST_NONE;
  80. retry:
  81.     seconds = ktime->seconds;
  82.     read_barrier();
  83.     tv->tv_usec = ktime->useconds;
  84.     read_barrier();
  85.     tv->tv_sec = ktime->seconds;
  86.     if (tv->tv_usec == 0 && seconds == tv->tv_sec &&
  87.         ktime->useconds2 != 0) {
  88.         read_barrier();
  89.         goto retry;
  90.     }
  91.  
  92.     if (seconds != tv->tv_sec)
  93.         tv->tv_usec = ktime->useconds;
  94.  
  95.     return 0;
  96. }
  97.